The present invention relates to powder actuated tools and, more specifically, to a method and a means for indexing a pre-loaded charge-carrying member so as to remove fired charges from the firing position and to introduce unfired ones therein.
Powder-actuated tools, of the general type employing pre-loaded power charge magazines, and, more specifically, of the type employing disk-shaped members fixedly carrying a number of cartridges projecting from a planar carrier, are known in the art. In such known tools, indexing of the charge magazine, especially the disk-type magazine, is accomplished by manipulation of an operating handle or through the action of a cam on, or cooperating with, a reciprocally mounted tool barrel. Tools of the first type are, however, seen to suffer in that magazine indexing adds another, inconvenient, step to the loading and firing sequence. Likewise, tools of the second type are seen to suffer in that pressing of the tool barrel against the work surface in preparation for firing, results in indexing of the magazine, even in the absence of trigger manipulation to fire the tool. Thus, if the user of this type of tool prepares to fire and then removes the tool from the work surface without having pulled the trigger, a live charge is indexed through the tool. The user must then discard the unused charge, a practise wasteful of material, or manually reposition the magazine, an awkward and inconvenient process. Further, in both of these types of tools, the indexing mechanisms are located in those tool areas most subject to accumulation of fouling matter, whereby the indexing mechanism may become difficult or, ultimately, impossible to operate.
It is, therefore, a primary object of the present invention to provide a powder-actuated tool of the aforementioned general type having magazine indexing means which will prevent indexing of an unfired charge through the tool.
It is a further object to provide such a tool wherein the indexing means is disposed in those tool areas least subject to fouling.
It is another object to provide such a tool wherein the indexing means is safe, comparatively simple in construction and highly reliable in use.
These objects are achieved, in general, by a tool wherein the indexing means is actuated by the same trigger displacement as actuates the firing mechanism. More specifically, means are provided for engaging the magazine which means is displaced from an initial position of engagement with a predetermined portion of the magazine consequent to a displacement of the trigger to fire the tool and is returned to the initial position, drawing the predetermined magazine portion therewith, consequent to the return of the trigger to its initial position. This return may be effected, most advantageously, by a spring which is loaded during the initial trigger movement.
In particular, the above-described motions of the magazine engaging means may be effected by a first rigid link, rotatably carried by the tool receiver, and a second rigid link member, rotatably carried by an extension formed on the trigger member; the links being rotatably pinned together, with the engagement means being disposed on a distal end of the first link. The engagement means may conveniently comprise a hook member adopted for abuttment against the portion of one of the cartridges projecting from the carrier, although oter means are within the contemplation of the present invention.
For keeping with the primary object of the invention, there is provided means for preventing indexing of the magazine unless the tool is pressed against the work surface preparatory to firing such that the reciprocally mounted barrel has been displaced to its rearwardmost position. This means may comprise means for constraining displacement of the aforementioned linkage. One such constraining means advantageously comprises an extension of the hinge pin, pining the two links, which extension is constrained to move in a recess, formed in the firing mechanism cocking slide, which slide is arranged for displacement in conjunction with the barrel. Alternatively, means may be provided to alter the configuration of the linkage so as to render the same incapable of effecting displacement of the magazine. One such means advantageously comprises a slot, formed in the receiver and adapted slidably and rotatably to receive the hinge pin of the first link, which slot is blocked, to prevent sliding of the pin, by an extension of the socking slide when the same is in its rearwardmost position, whereby the pivot point of the link is determined.